1 server.go

package main
import (
    "fmt"
    "net"
)
func main() {
    listen, err := net.ListenUDP("udp", &net.UDPAddr{
        IP: net.IPv4(0, 0, 0, 0),
        Port: 9090,
    })
    if err != nil {
        return
    }
    for {
        var data [1024]byte
        n, addr, err := listen.ReadFromUDP(data[:])
        if err != nil {
            break
        }
        go func() {
            fmt.Printf("addr:%v data:%v count:%v\n", addr, string(data[:n]), n)
            _, err = listen.WriteToUDP([]byte("received success!"), addr)
        }()
    }
}

2 client.go

package main
import (
    "fmt"
    "net"
    "time"
)
func main() {
    conn, err := net.DialUDP("udp", nil, &net.UDPAddr{
        IP: net.IPv4(192, 168, 1, 103),
        Port: 9090,
    })
    if err != nil {
        return
    }
    go func() {
        for {
            var data [1024]byte
            n, addr, _ := conn.ReadFromUDP(data[:])
            fmt.Printf("addr:%v data:%v count:%v\n", addr, string(data[:n]), n)
        }
    }()
    for i := 0; i < 100; i++ {
        fmt.Print("hi")
        _, err := conn.Write([]byte("hello server!"))
        if err != nil {
            return
        }
    }
    time.Sleep(time.Hour)
}